Atherectomy devices of various kinds have been used to break up and remove stenoses formed on the inner walls of the arteries of patients, particularly the coronary arteries. Some of these devices comprise catheters having rotary blades or the like on their distal end to cut through the stenosis and then, typically, to remove the stenosis through the lumen of the catheter, or by some other means.
Such atherectomy devices have typically been advanced along a guidewire in a manner that is similar in broad scope to the advancement of an angioplasty balloon catheter along a guidewire, in which the balloon is used to expand stenoses in arteries to improve the flow of blood therethrough. However, the current guidewires which are used with atherectomy devices having a distal, movable blade for cutting are lacking in handling characteristics, particularly torquability and steerability, which renders them more difficult to advance into narrow, convoluted arteries, particularly the coronary arteries which often are of that type. One reason for this is that many conventional designs of high torquability and high steerability guidewire cannot be safely used with a moving blade atherectomy device. Such known guidewires have a distal spring surrounding a distal tip end portion of the guidewire. Such guidewire should not be used with moving blade atherectomy devices, because of the danger that the moving blade may engage the guidewire spring within a patient's artery, with the potential for serious injury to the patient.
In accordance with this invention, a guidewire for an atherectomy device having a moving blade, specifically a rotary blade, is provided in which the guidewire may have state of the art torquability and steerability, making use of a distal spring as is conventional in some of the best guidewire designs. At the same time, the atherectomy device is prevented from advancing along the guidewire to such a degree that its moving blade can engage the guidewire spring.
Thus, the atherectomy device can be used by the physician with confidence that the atherectomy device will not engage a distal guidewire spring. Such a guidewire thus provides excellent torquability and steerability for access to narrow, occluded, convoluted arteries which cannot be reached by conventional atherectomy device guidewires. At the same time, the device is safe with respect to the blade engaging a guidewire distal spring or similar item. The physician does not need to worry at all about that risk, and thus is free to concentrate upon other aspects of the procedure.